Assembly line for producing a steel coffer from sheet metal plate

ABSTRACT

The assembly line for producing a steel coffer (2) for ceiling and/or wall structures, in particular for interior finishing and construction of ships, for transportable and movable buildings, for sheds, hotels and the like, from a sheet metal plate (1) comprises a cutting and/or stamping station (3), a bending press (4) with an associated manipulator (5) and an associated roller-ball table (6) and a welding station (7), as well as at least one trolley (8) in the form of an underfloor vehicle, an underfloor trolley, or the like, which can move back and forth under these stations (3, 5, 7). The bending press (4) is combined with a manipulator (5) designed as a semi-portal crane, which is movable with respect to this press (4) and has a gripper which is also movable, adjustable in height and rotatable around the height axis, by means of which the sheet metal plate (1) is fed in its required positions to the bending press (4). The bending press (4) has a hold-down device which can be swiveled to compensate various sheet metal thicknesses.

The invention relates to an assembly line (installation) by means ofwhich it is intended to produce steel coffers as finished components forceilings and/or wall structures at a plurality of stations in acontinuous run.

A large number of steel coffers is required as wall elements and bearingfloors in the course of erecting large buildings, as well as forinterior finishing and construction of buildings and ships, whichcoffers consist of multiply beveled steel sheets of a large length andwidth, which are to be provided with trough-openings and fastening holesand are to have welded-on reinforcing sections.

In actuality, this coffer production is performed elaborately by meansof a plurality of machines, and the known bending presses are notdesigned for beveling long sheets, so that the steel coffers are of onlysmall dimensions and therefore their number used is increased and thetotal construction is made more expensive.

It is the object of the invention to develop an assembly line, by meansof which it is possible to produce a steel coffer incorporating allrequired structural characteristics for later use, having a largesurface and made of various sheet metal thicknesses from a sheet metalplate in the course of an automatic run-through and at manipulableprocessing positions with short clock times in an efficient andeconomical manner.

This object is attained in accordance with the invention by thecharacterizing features of claim 1; the subsequent dependent claims 2 to6 contain advantageous further developments of the embodiment of theassembly line.

It is a further object of the invention to provide a bending press forbeveling of long sheet metal plates of different sheet metal thicknessesat an even bending pressure and large bending angles, which can beintegrated into the assembly line as a long multi-component.

This object is attained by the characteristic of claim 7 and thesubsequent claims 8 to 13 containing advantageous further developments.

A further object is considered to be the provision of a manipulatorcooperating with the bending press, which introduces the sheet metalplate into the bending press and removes it therefrom and has many freedegrees of movement.

This object is attained by means of claims 14 to 16.

One concept of the invention is seen to lie in the entire assembly line,a second, independent concept of the invention lies in the specialcharacteristics of the bending press, and a third concept of theinvention lies in the combination of the bending press with thespecially designed and operating manipulator.

By means of the assembly line of the invention it is possible to producein an efficient and economical manner large numbers of steel cofferswithin short clock times (clock time 17 min.), which have all structuralcharacteristics required for later use and a large-surface design.

The bending installation is one of several stations of the assembly lineand comprises three bending presses which can be coupled, an underfloortrolley (bogey truck), a manipulator and a roller-ball table.

The bending presses, having individual lengths of 4 m and operating inaccordance with the bending process, are individually controlled butdesigned in such a way that they can simultaneously work on theworkpiece (sheet metal plate) without gaps in the manner of a battery oftwo or three presses.

The manipulator is embodied as a movable semi-wall crane, has a movablegripping and rotating device for the sheet metal plate and positions itin the bending press without the need for stops. Manipulation of thesheet metal plate takes place in one processing plane. The sheet metalpiece or coffer is supported on the roller-ball table. The manipulatorhere needs only to overcome inertia and frictional resistance.

The job of the underfloor trolley, which can be moved along the X axisin an elongated gap of the roller-ball table, is to convey the sheetmetal piece always into the same position and to hand it over to themanipulator, as well as to take over an already bent coffer in the sameposition and to convey it on to the next station.

The bending press (one or a plurality of coupled bending presses) hasbeen optimized for bending sheet steel of approximately 4 toapproximately 6 mm and with a breaking resistance of 400 N/mm².

The bending power of the press is 850 kN. The press can be put under aload of 1200 kN for short periods of time, in which case it can also besupplied with a more powerful oscillating motor.

It is possible to assign each one of the three bending presses separateindividual press tables, or a common press table of 12 m length.

The bending press has a large pivot and work range of 600 mm with a freethrough-opening of the same size. To process a workpiece of a length of12 m, shorter and at the same time stable press units are used in thebattery of three presses.

Each press is mainly made of parts which are screwed together.

The rigid C-frame of the bending press is embodied as a welded structureand the total processing of the C-frame takes place in one chucking. Thescrewing surfaces for guides, oscillating motors and bearings are milledand turned.

The drive for the bending cheek is performed by two lateral doubletoothed quadrants. A hydraulic oscillating motor drives a torsion shaftin the center, on the ends of which pinion gears are fastened to theleft and right of the C-frame.

The bending press is designed for 90° bending. The size of the bendingcheek and the bending drive make pivoting around an angle of 120°possible. The bending cheek is guided in each C-frame via many supportrollers with spherical running surfaces and guide rollers witheccentrics. For improved load distribution, the support rollers withtheir fixable eccentric shafts are appropriately resilient. Sphericalrunning surfaces prevent loads on the edges of the rollers. The guiderollers are also resiliently mounted. They are mounted at a shortdistance from the guide rail, so that they are not subjected to thedeformation forces of the C-frame.

The bending forces are guided via the cheek and the bending cheek bodyas far as the support rollers.

The C-frame has a bearing above this roller guide for the bending cheek,in which an eccentric shaft is supported. The eccentric disks aredouble-seated in the eccentric eye of the connecting flange.

A blocking cylinder eye has been attached on the upper part of theflange. Each one of the eye flanges is screwed together with thehold-down device.

On one side of the center eccentric eye, the shaft can be driven by ahydraulic oscillating motor via a toothed reduction gear. A pivot leveris fastened on the eccentric shaft on the other side of the centereccentric eye. The hold-down device is pivoted away in a controlledmanner by the oscillating motor by means of a pivot lever. In the courseof this, the oscillating motor must be assisted by the blockingcylinders.

The deformation forces of the hold-down device and the C-frame are nottransmitted to the bearings.

The oscillating motor is screwed to the C-frame by means of the flange.

When bending narrow sheet metal plates, the manipulator is located inthe vicinity of the hold-down device. The hold-down device then does notpivot away freely. In this case pivoting must take place controlled andcoupled with the corresponding displacement of the manipulator. Thiscontrol is performed by the oscillating motor via the rotationtransmitter. The oscillating motor, together with the blocking cylindercauses the pivoting of the hold-down device.

First, the oscillating motor generates the hold-down force (the forcebetween the table and the hold-down device) via the eccentric. In thecourse of bending, it is reduced to a defined residual clamping force.During bending the oscillating motor is under oil pressure.

The blocking cylinder is automatically locked on the piston side as soonas it has moved into the end position.

It remains locked until the hold-down device is pivoted away. Theblocking cylinder has such dimensions that it can take up the hold-downreaction forces as well as the bending reaction forces.

The blocking cylinder with the eye flange, the hold-down device and theeccentric shaft with the bearings together form a coupling mechanismwhich is driven by the eccentric shaft. The position of the eccentrichas been set in such a way that an optimal setting of the foot of thehold-down device is possible for various sheet metal thicknesses. Thesize of the eccentric of approximately 12 mm has been set inconsideration of the necessary lift of approximately 15 mm of thehold-down device. Lifting makes the displacement, free of sliding, ofthe workpiece possible for follow-up bending.

A support surface for the guide rail carrier has been welded on abovethe blocking cylinder bearing on all C-frames of the bending machineformed by the bending presses. A surface for screwing on a guide railcarrier has also been formed at the bottom on the rear part of theC-frame. These surfaces allow the simultaneous connection of the threebending presses with the manipulator within the tolerances of processingexactness, which is of extraordinary importance for producing thecoffers. The bending machine together with the manipulator constitutes afunctional unit.

The job of the manipulator is to take over the sheet metal plate fromthe previous station, to service the bending press and to transfer theformed sheet metal plate for further processing, for example forinserting and welding transverse bows, trapezoidal sections, etc.

Manipulation of the sheet metal piece takes place in one processingplane. The sheet metal piece or coffer is supported on the roller-balltable. In the bending station, the workpiece is fed to the bendingmachine by the portal crane in the correct position. It is never liftedoff the roller-ball table. The sheet metal piece is merely received byclamping cheeks of the manipulator via two retaining bolts welded to thesheet metal piece. These bolts are parallel to the X axis and aretherefore in fixed connection with the coordinate system.

The sheet metal plate is cut and provided with holes in the laserstation. It is transferred along the X axis to the manipulator exactlyin the center of the roller-ball table by an underfloor trolley in thecenter of the transfer line. The retaining bolts are hollow.

Thus, the sheet metal piece is always moved into the same transferposition. Positioning of the manipulator can be selected to remainwithin rough limits, because the clamping cheeks (clamping chucks) havesufficiently large openings. For this reason the trolley guidance inthis station can be selected to be relatively simple.

The construction of the crane and the manipulator and the selection ofthe guide elements make possible highly exact positioning, so that thetolerance range and the assembly techniques are sufficient and nopositioning stops are needed on the roller-ball table and the bendingmachine.

The sheet metal processing technique in the preceding stations has beensimplified and made less expensive because of the design without stops.

The manipulator is embodied in welded full-box construction as asemi-portal crane with a support column. This design allows a lightconstruction.

An exemplary embodiment of the invention is shown in the drawings, shownis in:

FIG. 1, a top view of an assembly line for steel coffers, consisting ofa cutting and/or stamping station, a bending press with a manipulatorand a roller-ball table, and a welding station,

FIG. 2, a lateral view of the bending press with manipulator,

FIG. 3, a top view of the bending press with manipulator,

FIG. 4, a back view of the bending press with manipulator,

FIG. 5, a lateral view of the bending press with the hold-down devicepivoted downward into the clamping position (solid lines) and in thelifted position of the hold-down device in dash-dotted lines,

FIG. 6, a lateral view of the bending press with the hold-down devicepivoted up.

The assembly line for producing a steel coffer (2) for ceiling and/orwall structures, in particular for interior finishing and constructionof ships, for transportable and movable buildings, for sheds, hotels andthe like, from a sheet metal plate (1) comprises a cutting and/orstamping station (3), a bending press (4) with an associated manipulator(5) and an associated roller-ball table (6) and a welding station (7),as well as at least one trolley (8) in the form of an underfloorvehicle, an underfloor trolley, or the like, which can move back andforth under these stations (3, 5, 7).

A pre-treatment station (9) is disposed upstream of the cutting and/orstamping station (3), and a roller conveyor (10) is connected to thewelding station (7). All stations (9, 3, 4, 2 and 10) are disposedbehind each other in the pass-through direction (A) of the sheet metalplate (1) and result in a straight work run.

Notches (1a), openings (1b) and reamed holes (1c)--see FIG. 1--are cutinto the sheet metal plate (1) at the cutting and/or stamping station(3).

The circumferential edge of the sheet metal plate (1) is formed into asingly-- or multiply-beveled edge (1d)--see FIG. 1 in steps in thebending press (4), wherein the roller-ball table (6) is used as thesupport for the sheet metal plate (1) and the manipulator (5) grasps thesheet metal plate (1) at its fitting marks (1c), formed by the reamedholes (1c) and/or retaining bolts provided therein, and inserts it forthe individual forming steps into the bending press (4) and takes it outof it again; in the process the sheet metal plate (1) continues to lieon the roller-ball table (6) and only its position is changed(displacement or turning) in this support plane.

Reinforcement sections (2a) are placed in the formed sheet metal plate(1) in the welding station (7) at distances to form a grid and arecyclically welded--see FIG. 1--, after which the steel coffer (2) isfinished and is transported out of the assembly line by the rollerconveyor (10).

It is preferred to dispose two trolleys (8), which can be moved on acontinuous guide (11), under the stations (9, 3, 4, 6, 7 and 10),wherein the first trolley (8) operates on a movement path (FW1) startingat the pre-treatment station (9) and extending to the center of theroller-ball table (6), and thus the bending press (4), while themovement path (FW2) of the second trolley (8) extends from the center ofthe roller-ball table (6) into the area of the roller conveyor (10).

The trolleys (8) move the sheet metal plate (1) into the individualstations (3, 6, 7, 10) and stop there for processing of the sheet metalplate, or move on in steps.

The cutting and/or stamping station (3) has two carriages (13), whichcan move back and forth in the longitudinal direction (A) of the sheetmetal plate on guides (12) in a limited work area and respectively havetwo or a plurality of tools, preferably plasma/laser cutter heads,stamping or drilling tools, and guide rollers (15) are associated withthese carriages (13) for stops for the sheet metal plate in thelongitudinal direction and retractable stops (16) for the transversestop of the sheet metal plate, as well as collet chucks (17) for lockingin the aligned sheet metal plate (1) (FIG. 1).

The roller-ball table (6) is constituted by a table (6a) of largesurface, which adjoins the receiving side of the bending press (4),extends transversely to the run-through direction (A) of the sheet metalplate across the width of the adjoining stations (3, 7), takes up atleast the length of the bending press (4) and has a plurality of spheres(6b) rotatably seated in it.

The welding station (7) has a welding apparatus (18) containing aplurality of welding heads (19), to which a feed device (20) isassigned, which places the reinforcement sections (2a) into thepre-formed sheet metal plate (1) in an aligned manner; both devices (18,20) are adjustably seated on guides (21) in the run-through direction(A) of the sheet metal plate and are brought into their work positionsin synchronicity with the sheet metal plate (1) which is cyclicallytransported by the trolley (8).

The pre-treatment station (9) upstream of the cutting and/or stampingstation (3) is used to preform sheet metal plates (1), welding sheetmetal plates (1) together into a large-surface sheet metal plate (1),for sandblasting, or the like.

As can be seen from FIGS. 2, 5 and 6, the bending press (4) has a presstable (23) fixed in a C-frame (22), a hold-down device (24) movable inheight and a bending cheek (27) which is pivotable in height in a guide(26) around the horizontal bevel shaft (bending shaft) (25).

The hold-down device (24) is seated in the C-frame (22) with ahorizontal eccentric drive (28), pivotable in height by means of ahydraulic oscillating motor (29) and a blocking cylinder (30) which isactuated by a pressure medium.

By means of its eccentric drive (28), the hold-down device (24) can beadjusted with a small pivot stroke (H) in its pivoted-down clampingposition (solid lines in FIG. 5 and dash-dotted lines in FIG. 6), inwhich it cooperates with the press table (23), and independently ofpivot and blocking cylinders (30) which lock it in this clampingposition, with bending pressure for various thicknesses (S) of sheetmetal plates, and can be lifted (dash-dotted lines in FIG. 5) to releasethe sheet metal plate (1), and the hold-down device (24) is pivoted upinto the open press position (solid lines in FIG. 6) by means of itseccentric drive (28) and the released pivot and blocking cylinder (30).

The eccentric drive (28) has an eccentric shaft (31) rotatably seated inthe C-frame (22), on which a gear wheel (33), driven by a gear wheel(32) of the hydraulic oscillating motor (29) flanged on the C-frame(22), and an eccentric (34) with a rotary disk (35) and a driver (36)formed on it are seated; the hold-down device (24) is seated with aswivel bearing (37) around the eccentric (34) and is motionallyconnected with it, and the driver (36) of the eccentric (34) cooperatesin a non-positive manner with the swivel bearing (37) for pivoting thehold-down device upward.

The pivot and blocking cylinder (30) is located above the eccentricdrive (28) and is seated with its cylinder (30a) around a horizontalpivot shaft (38) on the C-frame (22), and hingedly engages with itspiston rod (30b) the swivel bearing (37) of the hold-down device (24) ina horizontal pivot shaft (39) above the eccentric (34).

The bending cheek (27) is seated on two pivot segments (40), which arerespectively positively guided in a crank guide (26) in the form of aroller guide extending on a circle in the C-opening (41) of the C-frame(22), are embodied as toothed quadrants and are pivotable in height viaa hydraulic pivot drive (42) with drive pinions (43) .

As shown in FIG. 4, the C-frame (22) is formed by three C-stands (22a),connected with each other by connecting pipes (44) and the press table(23), and maintained at a distance from each other. An eccentric drive(28) with a hydraulic oscillating motor (29) is seated on each C-stand(22a) and all three eccentric drives (28) are motionally connected by aneccentric shaft (31) acting as a torsion shaft.

A pivot and blocking cylinder (30) is seated on each C-stand (22a), andthe hold-down device (24) is supported via respectively a swivel bearing(37) by the eccentric drive (28) and is connected with the blockingcylinders (30). Thus, the bending press (4) has a total of threeeccentric drives (28) and three pivot and blocking cylinders (30).

The bending cheek (27) can be pivoted in height by means of pivotsegments (40), guided on the crank guide (26) of each C-stand (22a), anda central hydraulic oscillating motor (42) via a continuous torsiondrive shaft (43a), on which the drive pinions (43) are seated, whichmesh with the toothed pivot segments (40).

It is preferred to introduce into the assembly line a long bending pressconstituted by three or more aligned bending presses (4) which arecontrolled to operate synchronously and are combined into a modularcomponent, so that it is possible to bevel even very long sheet metalplates of up to 12 m in respectively one bending step.

The long bending press (4), formed of three presses (4), is illustratedin FIGS. 1, 3 and 4.

The manipulator (5) in accordance with FIGS. 1 to 4 is constituted by asemi-portal crane, which is movable, guided on upper and lower guides(45, 46) of the bending press (4), parallel to the bending edge (25) andwhich has, on its cantilevered arm (47) extending transversely to thedirection of movement (A) over the roller-ball table (6), a verticalgripper (49), which is movable in the longitudinal direction of thecantilevered arm (47), can itself be moved vertically and is rotatablearound its vertical axis (48), for gripping the sheet metal plate (1)which is to be fed to and removed again from the bending press (4) forthe individual bending steps.

The semi-portal crane (5) is supported with the lower end of its uprightsupport column (50) on the guide (45) disposed on the bottom of the backof the C-frame (22) facing away from the C-opening (41), and is seatedwith its cantilevered arm (47) in the guide (46) fixed on the top of theC-frame (22); both guides (45, 46) are formed by rails (profiledsection), on which the semi-portal crane (5) can be moved by means ofrollers (51).

The gripper (49) has a telescoping column (52), itself movable inheight, the upper end of which is supported, with the interposition of alive ring (53), on a carriage (54) which is movably suspended on acantilevered arm (47), and which column has on its lower end ahorizontal support arm (55) with two clamping chucks (56), disposedapart from each other and cooperating with the fitting marks (1c) of thesheet metal plate (1).

The drive for the manipulator (5) is indicated by (57) in FIG. 2, andthe end switches (58) for the limitation of the travel of themanipulator (5) are shown in FIG. 4.

Furthermore, the drive (59) for the carriage (54) and the drive (60) forthe live ring (53), as well as the hydraulic pump (61) assigned to themare illustrated in FIG. 2; the lift device (62), controlled by liftlimiting sensors (63), is disposed in the telescoping column (52).

The oscillating motor (29) for the eccentric drive (28) and theoscillating motor (42) for the bending cheek (27) are controlled byrotation transmitters (65, 66), and the pivot and blocking cylinder (30)is embodied with a control element (sensor) (64) for locking andreleasing its piston rod (30b) (FIG. 2).

The roller-ball table (6) is not shown in FIG. 2, instead the trolley(8) with its guide (11) is shown in dash-dotted lines.

The sheet metal plate (1), prepared in the pre-treatment station (9), ispulled into the cutting and/or stamping station (3) by the trolley (8)and is aligned on the guide rollers (15) and stops (16).

The two cutting and/or stamping devices (13, 14) prepare the notches(1a) in the corners of the sheet metal plate (1), and the openings (1b)and the reamed holes (1c) by means of plasma-- or CO₂ -laser cutting orby stamping and/or drilling.

In the process, the trolley (8) fixes the aligned sheet metal plate (1)by means of the chucks (17) and the two devices operate in a limitedwork area (X, Y), and the sheet metal plate (1) is moved on in steps(clocked movements) by the trolleys (8) after each work area (X, Y)until the entire length of the sheet metal plate has been worked.

Retaining bolts are inserted into the reamed holes (1c) and welded in.

Then the sheet metal plate (1) is transported on the roller-ball table(6).

The formed sheet metal plate (1) is now taken over by the manipulator(5), which services the bending press (4), for the individual bendingsteps. For this purpose the gripper (49) moves downward on the sheetmetal plate (1) and its clamping chucks (56) grip the fitting marks(1c), and then the sheet metal plate (1) is inserted into the openedbending press (4) for performing the first bending step whilemaintaining its seat on the roller-ball table (6).

Because the manipulator (5) can move the sheet metal plate (1) in theplane of the sheet metal plate by means of the semiportal crane and thegripper carriage (54), and can turn it by means of the live ring (53),the sheet metal plate (1) is displaced inside the bending press (4) foreach new bending step and, for making a new profiled edge section (1d),is taken out of the bending press (4), placed into the new position andreturned into the bending press (4) again, the manipulator (5) alwaysgrasping the sheet metal plate (1) by its fitting marks (1c).

The travel distance (MW) of the manipulator (5) extends over nearly theentire length of the bending press (4).

To perform each bending step for the profiled edge section (1d) of thesheet metal plate (1), the hold-down device (24) is pivoted down, firmlyclamps the sheet metal plate (1) between itself and the press table (23)and then the bending cheek (27) is pivoted upward in a controlledmanner.

Afterwards the bending cheek (27) is pivoted back downward and thehold-down device (24) is lifted, so that the sheet metal plate (1) canbe prepared in the press (4) for the subsequent bending step, anddisplaced.

When the profiled section (1d) has been finished on the one side of theplate, the manipulator (5) takes the sheet metal plate (1) out of thebending press (4), turns the sheet metal plate (1) around and againinserts it into the bending press (4) for bending the profiled sectionon the next side of the sheet metal plate, in the course of which thesame bending steps are repeated.

During each bending step the eccentric drive (28) keeps the pivoted-downhold-down device (24) under great pressure against the sheet metal plate(1) lying on the press table (23). In the process, the pivot andblocking cylinder (30) is extended and locked (FIG. 5).

The eccentric drive (28) is actuated by its oscillating motor (29) forlifting the hold-down device (24), i.e. for releasing the sheet metalplate (1) so it can be displaced in the C-opening (41) for thesubsequent bending step; in the process, the gear wheel (32) turns theeccentric shaft (31) via the gear wheel (33) and thus also the eccentric(34), and the pivot and blocking cylinder (30) remains locked in itsextended position during this.

Now, because of the rotation of the eccentric (34), the hold-down device(24) is positively lifted by its swivel bearing (37) seated around theeccentric (34) and is slightly lifted off the sheet metal plate (1) overa short lift-pivot path (H)--in the course of this the hold-down foot(24a) of the hold-down device (24) moves away from the bending edge (25)on a movement path which is directed obliquely upward and outward--at aninclination of approximately 45°--into the hold-down position shown bydash-dotted lines in FIG. 5, and the sheet metal plate (1) is releasedfor displacement.

The short lift-pivot path of the hold-down device (24) is made possibleby the hinged connection (29) with the pivot and blocking cylinder (30),in spite of its being locked.

The eccentric (34) is turned in the opposite direction for renewedclamping of the sheet metal plate (1) and in this way the hold-downdevice (24) is again pressed against the sheet metal plate (1).

This lift-pivot path (H) of the hold-down device (24) at the same timemakes possible the compensation for different thicknesses of sheet metalplates of approximately 4 to 10 mm, so that by means of the eccentric(34) the hold-down device (24) exerts the same high pressure on eachsheet metal thickness within the above mentioned thickness range.

With thinner or thicker sheet metal, the rotation of the eccentric (34)takes place at a smaller or larger angle of rotation and in this way theadaptation of the hold-down device (24) to the respective sheet metalthickness.

The pivot and blocking cylinder (30) is released for opening the bendingpress (4) and the eccentric drive (28) is turned further and, when itsdriver (36) pushes against the swivel bearing (37), the hold-down device(24) is pivoted upward.

The released cylinder (30) is retracted at the same time and supportsthe upward pivot movement of the hold-down device (24).

Based on the continuous eccentric shaft (31) and the disposition ofthree eccentric drives (28) of each bending press (4), which has alength of approximately 4 m, the parallel pivoting of the hold-downdevice (24) is assured, even in connection with short bending rangeswherein the hold-down device (24) acts on the sheet metal plate (1) onlywith a portion of its length; thus, no one-sided load on the hold-downdevice (24) is created. This also applies in connection with the longbending press (4) formed by three presses (4).

Beveling of the profiled edge sections (1d) on all four sides of thesheet metal plate (1) is made possible by the notches (1a) in thecorners.

After all bending processes have been completed, the manipulator (5)removes the formed sheet metal plate (1) and transfers it to the secondtrolley (8), which transports it to the welding station (7).

The trolley (8) moves the sheet metal plate (1), which is fixed in itsposition, in steps through this station (7), in which the feed device(20) inserts the reinforcement sections (2a) into the sheet metal plate(1) aligned at distances to form a grid, and then the welding device(18) welds the sections (2a) to the sheet metal plate (1) by means ofits controllable welding heads (19).

Subsequently the finished steel coffer (2) is moved out of the weldingstation (7) by the trolley (8) onto the roller conveyor (10) to be movedaway and the fabrication process is finished.

The finished steel coffer (2) constitutes a coffer element in a boxshape having a wall (2b) which itself is flat and a circumferential,multiply beveled profiled edge section (1d), and which has, beneath itsflat wall (2b), the reinforcement sections (2a) fastened there, has theopenings (1b) and connecting holes (1b) in the circumferential profilededge section (1d), and in the corners has notches (1a) for beveling theprofiled edge sections (1d) and for inserting supports, while beingprovided with fitting marks (1c) in the form of holes or bolts in itsflat wall (2b).

What is claimed is:
 1. An assembly line for producing a steel coffer forceilings and/or wall structures from a sheet metal plate,characterizedin that disposed successively in the run-through direction (A) of thesheet metal plate are a. a cyclically-operating cutting and/or stampingstation (3), which places notches (1a), openings (1b) and fitting marks(1c) into the sheet metal plate (1), b. a bending press (4), forming thesheet metal plate (1) into a singly- or multiply-beveled profiledsection (1d) in steps, with c. an associated roller-ball table (6) as asupport for the sheet metal plate, and with d. an associated manipulator(5), which grasps the sheet metal plate (1) at the fitting marks (1c) inthe form of reamed holes and/or retaining bolts, moves the sheet metalplate (1) in and transversely to the run-through direction (A) of thesheet metal plate in the plane of the sheet metal plate and rotates itaround a vertical axis (48) in the plane of the sheet metal plate,inserts the sheet metal plate (1) into the bending press (4) for theindividual forming steps and removes it again, and e. a welding station(7), which cyclically welds reinforcement sections (2a) at distances toform a grid into the formed sheet metal plate (1), and that f. at leastone trolley (8) is disposed underneath the cutting and/or stampingstation (3), the roller-ball table (6) and the welding station (7),which transports the sheet metal plate (1) in a straight line from oneto the other station (3 to 7), and, while stopped, maintains the sheetmetal plate (1) fixed in its position for the working steps in thecutting and/or stamping machine (3) and in the welding station (7),moves it in steps.
 2. An assembly line in accordance with claim 1,characterized in that the cutting and/or stamping station (3) has twocarriages (13), which can move back and forth in the longitudinaldirection (A) of the sheet metal plate on guides (12) in a limited workarea (X, Y) and respectively having two or a plurality of tools (14),and that guide rollers (15) on the long sides are associated with thiscarriage (13) for stops for the sheet metal plate in the longitudinaldirection and retractable stops (16) on the transverse sides for thetransverse stop of the sheet metal plate, as well as collet chucks (17)for locking in the aligned sheet metal plate (1).
 3. An assembly line inaccordance with claim 1, characterized in that the roller-ball table (6)is constituted by a table (6a) of large surface, which adjoins thereceiving side of the bending press (4), extends transversely to therun-through direction (A) of the sheet metal plate across the width ofthe adjoining stations (3, 7), takes up at least the length of thebending press (4) and has a plurality of spheres (6b) rotatably seatedin it.
 4. An assembly line in accordance with claim 1, characterized inthat the welding station (7) has a welding apparatus (18) containing aplurality of welding heads (19), and a feed device (20), which placesthe reinforcement sections (2a) to be welded into the pre-formed sheetmetal plate (1) in an aligned manner, that both devices (18, 20) areadjustably seated on guides (21) in the run-through direction (A) of thesheet metal plate and can be brought into their work positions insynchronicity with the sheet metal plate (1) which is cyclicallytransported by the trolley (8).
 5. An assembly line in accordance withclaim 1, characterized in that a pre-treatment station (9) is placedupstream of the cutting and/or stamping station (3) to preform sheetmetal plates, to weld sheet metal plates together into a large-surfacesheet metal plate (1), for sandblasting, or the like, and that a rollerconveyor (10), which moves the finished steel coffer (2) away, is placeddownstream of the welding station (7).
 6. An assembly line in accordancewith claim 1, characterized in that two trolleys (8) in the form ofunderfloor trolleys, which can be moved on a guide (11), are disposedunder the stations (3 to 10), wherein the movement path (FW1) of firsttrolley (8) extends from the pre-treatment station (9) to the center ofthe roller-ball table (6), and the movement path (FW2) of the secondtrolley (8) extends from the center of the roller-ball table (6) intothe area of the roller conveyor (10).
 7. An assembly line with a bendingpress in accordance with claim 1, the bending press (4) having a presstable (23) fixed in a C-frame (22), a hold-down device (24) movable inheight and a bending cheek (27) which is pivotable in height in a guide(26) around the horizontal bevel shaft (bending shaft 25).characterizedin that the hold-down device (24) is seated in the C-frame (22) with ahorizontal eccentric drive (28), pivotable in height by means of ahydraulic oscillating motor (29) and a pivoting and blocking cylinder(30) which is actuated by a pressure medium, and that by means of itseccentric drive (28), the hold-down device (24) can be adjusted with asmall pivot stroke (H) in its pivoted-down clamping position, in whichit cooperates with the press table (23), and independently of pivot andblocking cylinders (30) which lock it in this clamping position, withbending pressure for various thicknesses (S) of sheet metal plates, andcan be lifted to release the sheet metal plate (1), and that thehold-down device (24) can be pivoted up into the open press position bymeans of its eccentric drive (28) and the released pivot and blockingcylinder (30).
 8. A bending press in accordance with claim 7,characterized in that the eccentric drive (28) has an eccentric shaft(31) rotatably seated in the C-frame (22), on which a gear wheel (33),driven by a gear wheel (32) of the hydraulic oscillating motor (29)flanged on the C-frame (22), and an eccentric (34) with a rotary disk(35) and a driver (36) formed on it are seated, and that the hold-downdevice (24) is seated with a swivel bearing (37) around the eccentric(34) and is motionally connected with it, and the driver (36) of theeccentric (34) cooperates in a non-positive manner with the swivelbearing (37) for pivoting the hold-down device upward.
 9. A bendingpress in accordance with claim 8, characterized in that the pivot andblocking cylinder (30) is located above the eccentric drive (28) on theC-frame (22) and is seated with its cylinder (30a) around a horizontalpivot shaft (38), and hingedly engages with its piston rod (30b) theswivel bearing (37) of the hold-down device (24) in a horizontal pivotshaft (39) above the eccentric (34).
 10. A bending press in accordancewith claim 7, characterized in that the bending bar (27) is seated ontwo pivot segments (40), which are respectively positively guided in acrank guide (26) in the form of a roller guide extending on a circle inthe C-opening (41) of the C-frame (22), are embodied as toothedquadrants and are pivotable in height via a hydraulic pivot drive (42)with drive pinions (43).
 11. A bending press in accordance with claim 7,characterized in that the C-frame (22) is formed by three C-stands(22a), connected with each other by connecting pipes (44) and the presstable (23) and maintained at a distance from each other, that aneccentric drive (28) with a hydraulic oscillating motor (29) is seatedon each C-stand (22a) and that all three eccentric drives (28) aremotionally connected by an eccentric shaft (31) acting as a torsionshaft, and that a blocking cylinder (30) is seated on each C-stand (22),and that the hold-down device (24) is supported via respectively aswivel bearing (37) by the eccentric drive (28) and is connected withthe blocking cylinders (30).
 12. A bending press in accordance withclaim 7, characterized in that the bending cheek (27) can be pivoted inheight by means of pivot segments (40), guided on the crank guide (26)of each C-stand (22a), and a central hydraulic oscillating motor (42)via a continuous torsion drive shaft (43a), on which drive pinions (43)are seated, which mesh with the toothed pivot segments (40).
 13. Anassembly line in accordance with claim 1 , characterized in that thereinis disposed a long bending press (4) constituted of three or morealigned bending presses (4) which are controlled to operatesynchronously and are combined into a modular component.
 14. An assemblyline with a bending press and a manipulator associated with it inaccordance with claim 1, characterized in that the manipulator (5) isconstituted by a semi-portal crane (5), which is movable, guided onupper and lower guides (45, 46) of the bending press (4), parallel tothe bending edge (25), which has, on its cantilevered arm (47) extendingtransversely to the direction of movement (A) over the roller-ball table(6), a vertical gripper (49), which is movable in the longitudinaldirection of the cantilevered arm (47), can itself be moved verticallyand is rotatable around its vertical axis (48), for gripping the sheetmetal plate (1) which is to be fed to and removed again from the bendingpress (4) for the individual bending steps.
 15. A manipulator inaccordance with claim 14, characterized in that the semi-portal crane(5) is supported with the lower end of its upright support column (50)on the guide (45) disposed on the bottom of the back of the C-frame (22)facing away from the C-opening (41), and is seated with its cantileveredarm (47) in the guide (46) fixed on the top of the C-frame (22), andthat both guides (45, 46) are formed by rails (profiled sections), onwhich the semi-portal crane (5) can be moved by means of rollers (51).16. A manipulator in accordance with claim 15, characterized in that thegripper (49) has a telescoping column (52), itself movable in height,with a lifting device (62) disposed therein, the upper end of which issupported, with the interposition of a live ring (53), on a carriage(54) which is movably suspended on a cantilevered arm (47), and whichhas on its lower end a horizontal support arm (55) with two clampingchucks (56), disposed apart from each other and cooperating with thefitting marks (1c) of the sheet metal plate (1).
 17. An assembly line inaccordance with claim 2 characterized in that a pre-treatment station(9) is placed upstream of the cutting and/or stamping station (3) topreform sheet metal plates, to weld sheet metal plates together into alarge-surface sheet metal plate (1), for sandblasting, or the like, andthat a roller conveyer (10), which moves the finished steel coffer (2)away, is placed downstream of the welding station.
 18. An assembly linein accordance with claim 17 characterized in that two trolleys (8) inthe form of underfloor trolleys, which can be moved on a guide (11), aredisposed under the stations (3 to 10), wherein the movement path (FW1)of first trolley (8) extends from the pre-treatment station (9) to thecenter of the roller-ball table (6), and the movement path (FW2) of thesecond trolley (8) extends from the center of the roller-ball table (6)into the area of the roller conveyer (10).
 19. An assembly line inaccordance with claim 18, characterized in that therein is disposed along bending press (4) constituted of three or more aligned bendingpresses (4) which are controlled to operate synchronously and arecombined into a modular component.
 20. A bending press in accordancewith claim 11, characterized in that the bending cheek (27) can bepivoted in height by means of pivot segments (40), guided on the crankguide (26) of each C-stand (22a), and a central hydraulic oscillatingmotor (42) via a continuous torsion drive shaft (43a), on which drivepinions (43) are seated, which mesh with the toothed pivot segments(40).
 21. The assembly line according to claim 2, wherein the tools (4)includes selectively plasma/laser cutter heads, stamping tools, anddrilling tools.